Anesthesia for interventional bronchoscopic procedures

Introducing the bronchoscope into the airway has proved to be a challenge since the invention of the first bronchoscope. Airway reflexes, such as the gag reflex, cough, laryngospasm, hemodynamic alteration, and the associated anxiety stimulated by the passage of the bronchoscope into the airway, forced the bronchoscopist to be skilled and quick to perform the procedure [1]. As a result interest emerged in using anesthesia to ameliorate the airway reflexes and patient’s anxiety associated with bronchoscopy. A wide range of anesthesia techniques were developed to accommodate a variety of interventional bronchoscopic procedures such as simple diagnostic bronchoscopy, advanced diagnostic bronchoscopy, therapeutic bronchoscopic interventions, and pleural procedures. Anesthesia for interventional bronchoscopy varies from local anesthesia as the sole anesthetic modality to moderate sedation/analgesia (“conscious sedation”) with or without local anesthesia to general anesthesia [2]. Moderate sedation/analgesia (“conscious sedation”) is defined by the American Society of Anesthesiologist (ASA) as “a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained” [3]. Moderate sedation may progress to deep sedation/analgesia or even general anesthesia during the same procedure. Once under deep sedation, “the patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained” [3]. At the other end of the spectrum is general anesthesia, where “patients are not arousable, even by painful stimulation.” The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired [3].